Using both meal prep and meal prep keto for meal replacement and added fat burning. Alternating between a high carb and a high fat meal will allow you to switch up the substrates used. High carb means insulin is present.
Though meal prep is low gi, it still has carbs which will be the fuel source used after consuming this. However if you then switch over to meal prep keto, you will keep insulin low, which then enables you to use fat as the fuel source.
Meal prep regular before and after training and meal prep keto outside of those times will enable you to hit your calories whilst not overloading your body with carbs.